Behind the scenes at the Crown Prosecution Service
4 April 2013 Last updated at 09:30 BST
If the Crown Prosecution Service is effectively the law firm the nation turns to to prosecute crime, Treasury Counsel are the elite group of barristers the CPS turns to to prosecute the most serious and dangerous crimes.
They are the best of the best and work out of the Old Bailey.
The BBC's Legal Correspondent Clive Coleman went to see Brian Altman QC, who is soon to retire as First Senior Treasury Counsel, a post that that has seen him prosecute some of the biggest and most notorious criminal cases of recent times.
First broadcast on BBC Radio 4's Today programme on Thursday 4 March 2013.